Cod sursa(job #1526458)
Utilizator | Data | 16 noiembrie 2015 12:22:26 | |
---|---|---|---|
Problema | Fractii | Scor | 100 |
Compilator | cpp | Status | done |
Runda | Arhiva de probleme | Marime | 0.42 kb |
#include <fstream>
using namespace std;
long long nr;
long a[1000001], n, i, j;
int main()
{
ifstream f("fractii.in");
ofstream g("fractii.out");
f >> n;
for (i = 1; i <= n; i++)
a[i] = i - 1;
for (i = 2; i <= n; i++) {
for (j = 2 * i; j <= n; j += i)
a[j] -= a[i];
nr += a[i];
}
g << 2 * nr + 1;
f.close ();
g.close ();
return 0;
}